JP5386710B2 - Bag-in-box package of one-component moisture-curable resin composition - Google Patents

Description

  The present invention relates to a bag-in-box package of a moisture curable resin composition in which a spout is not easily detached from a bag. In particular, the present invention relates to a bag-in-box package of a moisture curable resin composition using polyethylene as a heat welding resin.

  A one-component moisture-curable resin composition is a viscous liquid before curing, and is a composition that is cured by the action of moisture in the air to produce a solid such as a rubber-like material. It is used. Since the moisture curable resin composition is cured by moisture in the air, a container having a water vapor impermeable layer such as a metal container or an aluminum layer or a soft resin container is used as the container.

  In the case of a small amount of moisture-curable resin composition, a cartridge or a soft resin-based bag is used. For example, in the case of a large amount of moisture-curable resin composition having a volume of 2 liters or more, a metal pail can or a plastic Large containers such as pail cans are used. However, a large container such as a pail can has a problem that the container weight is heavy and the disposal process is not easy.

  As disclosed in Patent Document 1, as a container for a relatively large amount of liquid, a light-weight bag-in-box that can be easily disposed of, that is, an inner container made of soft plastic such as polyethylene having flexibility is provided. In addition, a container using a cardboard box or the like as an exterior is used. An example of a container in a bag-in-box is shown in FIGS. Bag-in-boxes are used as industrial liquid containers in the food field such as soy sauce, sauce, liquor, and soft drinks, and in industrial fields such as developer and battery solution, but they can also be used as adhesive containers. .

  A spout for discharging the contents is usually attached to the soft plastic inner container of the bag-in-box. The spout is separately manufactured by injection molding or the like, and attached to the polyethylene film of the main body of the inner container. As an attachment method, a method of mechanical attachment by caulking, a method of attachment by thermal welding, a method of attachment by an adhesive, and the like are conceivable.

  As a method of mechanically attaching by caulking, for example, as shown in FIG. 4, the inner container film 6 is inserted into a groove on the outer periphery of the cylindrical spout 2, and a ring-shaped fastening member 5 is used to caulk the inner container. There is a method of sealing the spout on the film. Since this method mechanically seals, there is an advantage that it can be used regardless of the type of film in the inner container. In addition, in the method of attachment by thermal welding, as disclosed in paragraph [0026] of Patent Document 2, there is a risk of generating pinholes due to missing seals. Absent. Furthermore, compared with the method of attaching the film and spout using an adhesive, this method does not use an adhesive, so the components in the curable resin composition may dissolve or alter the adhesive. There are no advantages.

  When a bag-in-box with a spout attached by caulking is used as a container for an aqueous curable resin composition such as a resin emulsion adhesive, it can be used without any problem for a long period of time. However, when used as a container for a moisture curable resin composition, it has been found that, unlike a case of an aqueous curable resin composition, the spout may be easily detached from the inner container body after long-term storage. When it may come off easily, it may be difficult to connect the spout to the applicator of the curable resin composition when using the curable resin composition. When the bag-in-box is used for storing the moisture-curable resin composition, the reason why the spout is detached from the inner container body is not clear, but in the case of the moisture-curable resin composition, unlike the water-based composition, Since the components are in direct contact with the film of the inner container, it is presumed that the components of the composition become film lubricants and softeners and the spout is detached from the inner container body. In the case of an aqueous composition, it is considered that such a problem does not occur because the components of the composition are prevented from coming into direct contact with the film of the inner container by the aqueous medium.

JP 7-315436 A JP 2002-29546 A

  An object of the present invention is a bag-in-box container for a one-pack type moisture curable resin composition having a spout, wherein the spout is not detached from the inner container after the curable resin composition is stored in the container. It is to provide a box container.

  By using a bag-in-box container in which a polyethylene resin layer serving as a spout and a bag body is joined by heat welding, the present inventors have stored a one-part moisture-curable resin composition in a container for a long period of time. However, it has been found that the spout does not come off the inner container body. That is, the present invention relates to the following package.

Claim 1: One-pack type moisture-curable crosslinkable silyl group-containing organic polymer composition in a soft plastic inner container having a spout and comprising a laminated film comprising a polyethylene resin layer and an ethylene / vinyl alcohol copolymer layer A bag-in-box package that contains an object, wherein the polyethylene resin layer of the soft inner container and the spout are joined by heat welding.
The package according to any one of claims 1 to 3 , wherein the spout is a spout having a screw lid to which the spout can be attached.

[2] The package according to [ 1], wherein the polyethylene resin layer is a layer made of linear low density polyethylene.

[3] The package according to [ 2] , wherein the linear low density polyethylene is a linear low density polyethylene polymerized using a single site catalyst.

[4] The package according to any one of [1] to [ 3] , which is a spout having a screw lid to which the spout can be attached.

  The package of the present invention has an effect that the spout does not come off from the inner container body even when the one-pack type moisture curable resin composition is stored as a content for a long period of time.

It is a perspective view which shows an example of the polyethylene resin inner container for bag-in-boxes. It is a perspective view which shows the state which folded the inner container shown in FIG. It is an expansion perspective view of a spout. It is explanatory drawing of the joining method of the spout to the inner container main body by crimping. It is explanatory drawing of the joining strength measurement method of an inner container main body and a spout.

  The soft plastic inner container used in the present invention includes a polyethylene resin layer. Polyethylene is inexpensive and flexible, and has excellent mechanical strength. Examples of the polyethylene resin include various known polyethylenes such as high-pressure low-density polyethylene, high-density polyethylene, and linear low-density polyethylene.

  The high-pressure low-density polyethylene is flexible and can be used in the inner container made of polyethylene resin used in the present invention, but has poor heat-weldability and may generate pinholes. Therefore, it is preferable to use linear low density polyethylene (LLDPE) which is flexible and has excellent heat weldability and high film strength. In particular, linear low-density polyethylene obtained by polymerizing with a single site catalyst such as a metallocene catalyst is more excellent in heat weldability and film strength. Most preferred is a low-density polyethylene.

  The film including the polyethylene resin layer may be a single layer film or a laminated film with another resin. Examples of the other resin include polyamide resin, ethylene-vinyl alcohol copolymer resin (EVOH), ethylene-maleic anhydride copolymer resin, and vinylidene chloride resin. In the case of a single layer film of polyethylene resin, it is flexible, but when the contents are stored, the deformation of the container shape may be large. In the case of a laminated film, although it becomes a somewhat rigid film, it is preferable because the container shape is rarely deformed. In particular, when a laminated film having a polyethylene resin layer and an ethylene-vinyl alcohol copolymer resin layer is used, there is little content remaining in the container when the curable resin composition is poured out (when taken out), and the curable resin composition There is an advantage that things are not wasted.

  The laminated film can be produced by a dry lamination method, an extrusion lamination method, a coextrusion method or the like. In addition, a film including a polyethylene-based resin layer can be laminated with a metal layer such as aluminum and an inorganic compound layer such as silicon oxide or aluminum oxide in order to block oxygen and water vapor.

  The shape of the polyethylene resin inner container may be a molded container as shown in FIG. 1 obtained by vacuum molding or blow molding of a molten resin, or a bag obtained by thermally welding a film. Examples of the bag obtained by heat welding the film include a gusset bag, a flat bag, and a standing pouch. The inner volume of the polyethylene resin inner container is preferably 1 to 40 liters, particularly preferably about 2 to 20 liters. In the case of an inner container made of polyethylene resin of about 2 to 20 liters, a container having a substantially rectangular parallelepiped shape as shown in FIG. In the case of a polyethylene resin inner container of about 2 to 20 liters, the thickness of the film is preferably 10 to 300 microns, and more preferably 50 to 200 microns.

  The polyethylene resin inner container used in the present invention has a spout for storing and taking out the contents. The material of the spout can be used without limitation as long as it can be thermally welded to the polyethylene resin used for the film of the polyethylene resin inner container, but a polyolefin resin such as a polyethylene resin or a polypropylene resin is preferable. Polyethylene resins are particularly preferable.

  The spout is attached to the film of the polyethylene resin inner container by heat welding. For example, a spout having a flange portion of a heat-weldable material manufactured by separate injection molding or the like as shown in FIG. It is attached by stacking it on a bag and heat-welding the flange. The heat welding may be performed by a heat welding machine such as ultrasonic heat welding, or in the case of a molded container, heat welding may be performed on the molten resin at the time of blow molding or the like. The spout can be sealed by a closing means such as a cap. Usually, the cap is attached to the spout by screwing.

  Further, a handle may be provided in the polyethylene resin inner container in order to facilitate the operation of storing the polyethylene resin inner container in a container such as cardboard. In order to provide a handle, for example, a method in which a heat-welded portion of the film constituting the polyethylene resin inner container protrudes in an ear shape and a hole is formed through the protrusion to form a handle, or separately formed And a method of fixing the molded product to the inner container made of polyethylene resin.

  Examples of the one-pack type moisture curable resin composition that is the contents of the package of the present invention include a crosslinkable silyl group-containing organic polymer, a crosslinkable silyl group-containing polysiloxane, and an isocyanate group-containing urethane prepolymer. A curable resin composition contained as a main component can be given.

  The crosslinkable silyl group-containing organic polymer is, for example, a polymer having a crosslinkable silyl group represented by the general formula (1). The number of crosslinkable silyl groups is preferably 0.5 or more, more than 0.5 and 3 or less per polymer molecule. This polymer is in a liquid state before being cured, but the crosslinkable silyl group is hydrolyzed by moisture in the air, passes through silanol, and crosslinks and cures by forming siloxane bonds between the organic polymers.

（式中、Ｒ１は、炭素数１〜２０のアルキル基、炭素数３〜２０のシクロアルキル基、炭素数６〜２０のアリール基、炭素数７〜２０のアラルキル基またはＲ１３ＳｉＯ−（Ｒ１は、前記と同じ）で示されるトリオルガノシロキシ基を示し、Ｒ１が２個以上存在するとき、それらは同一であってもよく、異なっていてもよい。Ｘは水酸基または加水分解性基を示し、Ｘが２個以上存在するとき、それらは同一であってもよく、異なっていてもよい。ａは１、２又は３の整数である。）

(In the formula, R1 is an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, an aralkyl group having 7 to 20 carbon atoms, or R13SiO- (R1 is The same as above, and when two or more R1 are present, they may be the same or different, X represents a hydroxyl group or a hydrolyzable group, and X When two or more are present, they may be the same or different. A is an integer of 1, 2 or 3.)

  Examples of the main chain of the crosslinkable silyl group-containing organic polymer include polyoxyalkylene polymers such as polyoxypropylene, vinyl polymers such as acrylic and / or methacrylic acid ester polymers and polyisobutylene, and polyisoprene. And diene polymers such as polybutanediene, polyester polymers, polysulfide polymers, and mixtures thereof.

  The number-average molecular weight of the crosslinkable silyl group-containing organic polymer is 1,000 or more, particularly 6,000 to 30,000, because the viscosity before curing is low, and it is easy to handle, and the strength, elongation, modulus, etc. after curing It is suitable because of its excellent physical properties. In particular, those having a narrow molecular weight distribution are preferable because the viscosity is low even if the molecular weight is high.

  Among crosslinkable silyl group-containing organic polymers, polyoxypropylene polymers and mixtures of polyoxypropylene polymers and acrylic and / or methacrylic ester polymers are industrially manufactured and sold, and are easily available. .

  The crosslinkable silyl group-containing polysiloxane is also called room temperature curable organopolysiloxane, and is a polymer having a main chain of organopolysiloxane and containing 0.5 or more crosslinkable silyl groups in the molecule. This polymer includes one-pack type silicone resin containing an organopolysiloxane having a silanol group at the terminal and a crosslinkable silyl group-containing low molecular weight compound as a crosslinking component. The number average molecular weight of the crosslinkable silyl group-containing polysiloxane is 1,000 or more, particularly 6,000 to 30,000, which is easy to handle because of its low viscosity before curing, and has physical properties such as strength, elongation and modulus after curing. It is suitable because it is excellent.

  The isocyanate group-containing urethane-based prepolymer is one in which an isocyanate group reacts with moisture to form a urea bond to be crosslinked and cured, and includes an organic polyisocyanate, a polymer polyol, and optionally a chain extender. Those obtained by reacting with active hydrogen (group) under an excess of isocyanate groups are preferred. The isocyanate group content of the isocyanate group-containing urethane prepolymer is preferably 0.1 to 15.0% by weight, more preferably 0.3 to 10.0% by weight. In the synthesis of the isocyanate group-containing urethane prepolymer, a known urethanization catalyst or an organic solvent can be used.

  Examples of organic polyisocyanates include aromatic diisocyanates such as diphenylmethane diisocyanate and toluene diisocyanate, aliphatic diisocyanates such as 1,6-hexamethylene diisocyanate, aromatic aliphatic diisocyanates such as xylylene diisocyanate, cyclohexyl diisocyanate, isophorone diisocyanate, and hydrogenation. And alicyclic diisocyanates such as toluene diisocyanate. These adduct-modified products, burette-modified products, isocyanurate-modified products, uretonimine-modified products, uretdione-modified products, and carbodiimide-modified products can also be used. Furthermore, polymeric bodies, such as polymethylene polyphenyl polyisocyanate, can also be used. These can be used alone or in combination of two or more.

  Examples of the polymer polyol include polyester polyols, polyester amide polyols, polycarbonate polyols, polyether polyols, polyolefin polyols, acrylic polyols, animal and plant polyols, copolyols thereof, and the like, or a mixture of two or more thereof. Of these polymer polyols, polyether polyols are preferred because of their excellent workability, adhesion, water resistance, weather resistance, and the like. Preferred examples of the chain extender include low molecular alcohols, low molecular amines, low molecular amino alcohols having a molecular weight of less than 500, and mixtures of two or more thereof.

  In the one-component moisture-curable resin composition used in the present invention, various additives are usually blended. Examples of such additives include curing accelerators, thixotropic agents, fillers, plasticizers, diluents, adhesion promoters, and colorants. Many of these additives have a low molecular weight organic compound, and when the one-component moisture curable resin composition is stored in an inner container made of polyethylene resin, the low molecular weight organic compound directly contacts the container material. Therefore, when using an inner container made of polyethylene resin with the spout attached by mechanical means such as caulking, these low molecular weight organic compounds penetrate into the spout and the soft plastic film, and the bonding strength between the spout and the soft plastic film. Is considered to decrease.

(One-part moisture curable resin composition production example)
As a crosslinkable silyl group-containing organic polymer, 100 parts by weight of commercially available methyldimethoxysilyl group-terminated polypropylene oxide (manufactured by Kaneka Co., Ltd., trade name: Kaneka MS Polymer) and heavy calcium carbonate (Shiraishi Calcium Co., Ltd.) as a filler ), Product name: Whiten SB) 20 parts by weight, also as a filler, fatty acid-treated calcium oxide (manufactured by Maruo Calcium Co., Ltd., product name: Calfine 200), hindered phenol antioxidant as an antioxidant ( Ciba Japan Co., Ltd., trade name: Irganox 245) 1 part, paraffinic diluent (Japan Energy Co., Ltd., trade name: Cactus normal paraffin N-11) 10 parts by weight, adhesive N-β- (aminoethyl) γ-aminopropyltrimethoxysilane (Shin-Etsu Chemical Co., Ltd.) ), Trade name: Shin-Etsu Silicone KBM603) 6 parts by weight was added and mixed with stirring. Subsequently, 1 part by weight of tetraethoxysilane (manufactured by Colcoat Co., Ltd., trade name: ethylsilicate 28) as a dehydrating agent is added to the mixture, and a dioctyltin-based curing catalyst (manufactured by Nitto Kasei Co., Ltd., trade name: Neostan U) is used as a curing catalyst. -830) 2 parts by weight was added, and the mixture was stirred and mixed for 30 minutes under a nitrogen stream to obtain an adhesive composition.

(Aqueous resin composition production example)
In a reaction vessel equipped with a stirrer, reflux condenser, thermometer, and dropping funnel, 112 parts by weight of water, 80 parts by weight of a 15% by weight aqueous solution of polyvinyl alcohol (polyvinyl acetate having a saponification degree of 88%) as a stabilizer, and 0.6 parts by weight of sodium acetate was charged and heated with stirring. When the temperature reached 65 ° C., an aqueous potassium persulfate solution (0.2 parts by weight as potassium persulfate) was added as a catalyst. The addition of 100 parts by weight of vinyl acetate monomer was started simultaneously with the addition, and the addition of the entire amount was completed in 3 hours. During the dropping of the monomer, the temperature of the system was kept at 75 ° C., and stirring was continued at the same temperature for 1 hour after the dropping was completed to complete the polymerization. The polymerization rate of the vinyl acetate monomer was 99.5% or more. To the polymerization system after completion of the polymerization reaction, 10 parts by weight of diisobutyl adipate as a plasticizer was added during the cooling (while the temperature of the system was 70 to 60 ° C.).

(Measurement method of joint strength between inner container body and spout)
The contents are removed from the inner container, and about two-thirds of the lower part of the inner container body is excised. As shown in FIG. 5A, an iron bar having a diameter of 5 mm is passed through the center line of the cylindrical spout so as to be perpendicular to the center line. The upper part from the threaded flange of the cylindrical outlet of FIG. 5A is slid from the front opening of the measuring jig shown in FIG. 5B and inserted into the measuring jig. An iron rod is also inserted into the measurement jig, but the iron rod is used to prevent the threaded flange from being deformed during the tensile test and separating the spout from the measurement jig. The chuck holding portion of the measuring jig is held by one chuck of the tensile tester. The lower end of the inner container body is sandwiched between the other chucks of the tensile tester and stretched at 200 mm / min to measure the attachment strength between the inner container body and the spout. When the spout and the inner container main body are sufficiently joined, the spout and the inner container main body are not separated, the bag main body is broken, and when insufficient, the spout and the inner container main body are separated.

(Method for measuring the amount of the remaining curable composition at the time of dispensing the curable composition)
The weight of the inner container that does not contain the curable composition and the inner container that contains the curable composition are measured in advance. A discharge tube is attached to the inner container outlet containing the curable composition, and the whole inner container is placed in a pressurized container that can be pressurized with air. The air pressure is increased to 0.6 MPa in absolute pressure, and the contents are taken out from the discharge tube. The weight of the inner container in which the amount of the curable composition remains is measured, and the amount of the remaining curable composition is measured.

  As the film of the inner container body, a laminated film having a thickness of about 150 μm having a polyethylene resin layer, an ethylene-vinyl alcohol copolymer resin layer, and an ethylene-maleic anhydride copolymer resin layer is used, and the internal volume in the shape shown in FIG. An inner container having a weight of about 60 g and having an inner diameter of 32 mm and a spout having an inner diameter of 32 mm joined to the inner container body by thermal welding was filled with the resin composition produced in the above one-part moisture-curable resin composition production example. . The resin composition was immersed in a heat welded portion of the inner container body and the spout, and stored for 2 weeks in a constant temperature and humidity chamber adjusted to 50 ° C. and 85% RH. In order to prevent the curable resin composition from being cured by moisture in the air, the inner container was placed in an aluminum foil / polyethylene laminated film bag and the bag was thermally welded to prevent contact with moisture. After storage, the bonding strength between the inner container body and the spout was measured. The bag body was broken, and the spout and the inner container body were sufficiently joined. The residual curable resin amount was 50 g.

(Comparative Example 1)
As the film of the inner container body, a laminated film having a thickness of about 150 μm having a polyethylene resin layer, an ethylene-vinyl alcohol copolymer resin layer, and an ethylene-maleic anhydride copolymer resin layer is used, and the internal volume in the shape shown in FIG. The resin composition produced in the above-mentioned one-part moisture curable resin composition production example was filled in an inner container having a weight of about 60 g in which an outlet having an inner diameter of 32 mm was joined to the inner container body by caulking. The resin composition was immersed in a heat welded portion of the inner container body and the spout, and stored for 2 weeks in a constant temperature and humidity chamber adjusted to 50 ° C. and 85% RH. In order to prevent the curable resin composition from being cured by moisture in the air, the inner container was placed in an aluminum foil / polyethylene laminated film bag and the bag was thermally welded to prevent contact with moisture. After storage, the bonding strength between the inner container body and the spout was measured. The spout was separated from the inner container body at the caulking portion, and the joining of the spout and the inner container body was insufficient. In addition, if the joint strength between the inner container main body and the spout is measured immediately after filling the inner container with the curable composition without being stored in a thermo-hygrostat for two weeks, the bag main body breaks, and the outlet and the inner container main Bonding was sufficient. The residual curable resin amount was 70 g, which was not significantly different from that in Example 1.

(Comparative Example 2)
As a film of the inner container body, a laminated film having a thickness of about 150 μm having a polyethylene resin layer and a polyamide resin layer is used. The shape shown in FIG. 1 has an inner volume of about 5 L, and a spout with an inner diameter of 32 mm is caulked. An inner container having a weight of about 80 g joined to the main body was filled with the resin composition produced in the above-mentioned one-part moisture curable resin composition production example. This inner container was more flexible than the inner container used in Example 1. The resin composition was immersed in a heat welded portion of the inner container body and the spout, and stored for 2 weeks in a constant temperature and humidity chamber adjusted to 50 ° C. and 85% RH. In order to prevent the curable resin composition from being cured by moisture in the air, the inner container was placed in an aluminum foil / polyethylene laminated film bag and the bag was thermally welded to prevent contact with moisture. After storage, the bonding strength between the inner container body and the spout was measured. The spout was separated from the inner container body at the caulking portion, and the joining of the spout and the inner container body was insufficient. Further, the residual curable resin amount is 220 g, and the residual resin amount is larger than when a laminated film having a polyethylene resin layer, an ethylene-vinyl alcohol copolymer resin layer and an ethylene-maleic anhydride copolymer resin layer is used. It was.

(Reference Example 1)
The inner container similar to the inner container used in Comparative Example 1 was filled with the resin composition produced in the aqueous resin composition production example. After the resin composition is immersed in the heat-welded part of the inner container body and the spout and stored in a constant temperature and humidity chamber adjusted to 50 ° C. and 85% RH for 2 weeks, the bonding strength between the inner container body and the spout Was measured. The bag body was broken, and the spout and the inner container body were sufficiently joined.

(1) Inner container made of polyethylene resin for bag-in-box (2) Outlet (3) Outlet and heat-welded part of inner container made of polyethylene resin (4) Flange part (5) Clamping ring-shaped fastening member (6) Inner container film 7 Screw part flange 8 Iron bar 9 Measuring jig 10 Inside measuring jig 11 Chuck clamping part

Claims (4)

One-pack type moisture-curable crosslinkable silyl group-containing organic polymer composition is housed in a soft plastic inner container having a spout and made of a laminated film including a polyethylene resin layer and an ethylene / vinyl alcohol copolymer layer . A package in which a polyethylene resin layer and a spout of a soft inner container are joined by heat welding. The package according to claim 1, wherein the polyethylene-based resin layer is a layer made of linear low-density polyethylene. The package according to claim 2 , wherein the linear low density polyethylene is a linear low density polyethylene polymerized using a single site catalyst. The package according to any one of claims 1 to 3 , wherein the spout is a spout having a screw lid to which the spout can be attached.

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